Steering apparatus for motor vehicle

ABSTRACT

In a steering apparatus for a vehicle in which an inner column is supported to be movable in the axial direction by an outer jacket supported by a body-side bracket and a steering shaft is fixed to an adjustment position by clamping the inner column by the use of telescopic clamping means through the outer jacket, the outer jacket is provided with a slit entirely along the axial direction thereof.

TECHNICAL FIELD

The present invention relates to a steering apparatus of a tilt and/ortelescopic scheme for a vehicle.

BACKGROUND ART

In Japanese Patent Application Laid-Open No. 2001-347953, in a steeringapparatus of a tilt and/or telescopic scheme for a vehicle, anupper-side inner column is slidably fitted in a lower-side outer jacketfixed to the vehicle body. It is arranged such that the lower-side outerjacket and the upper-side inner column can be tilted together and theupper-side inner column can telescopically slide with respect to thelower-side outer jacket fixed to the vehicle body.

The lower-side outer jacket has a pair of clamp portions which are fixedto a part thereof at the rear side of the vehicle. At the time of tiltand/or telescopic clamping, these paired clamp portions are caused toapproach each other so as to embrace the upper-side inner column to befixed by clamping.

Further, since it is necessary to prevent the upper-side inner columnfrom rotating with respect to the lower-side outer jacket fixed to thevehicle body, and also to provide a stopper for telescopic adjustment, aprojection or a bolt formed on the lower-side outer jacket is engagedwith an axial groove which is formed on the upper-side inner column in apart on a more frontal side of the vehicle than the clamp portions.

In Japanese Patent Application Laid-Open No. 6-219283, in a telescopictype steering apparatus for a vehicle, an upper surface having asubstantially M shape of a distance bracket which has grooves extendedin the axial diction for telescopic adjustment on both sides thereof isattached to a lower side of a steering column by welding. The steeringcolumn is arranged to be telescopically slidable, together with thedistance bracket, with respect to a body-side bracket. At telescopicclamping, the steering column can be fixed by clamping a clamping boltwhich is inserted through the grooves for telescopic adjustment of thedistance bracket to thereby press the distance bracket on the body-sidebracket with pressure.

Further, the distance bracket and the body-side bracket are in pressurecontact with each other at flat surfaces thereof, so as to serve toprevent rotation of the steering column. At the same time, the clampingbolt is passed through the grooves for telescopic adjustment of thedistance bracket so as to play the role of a stopper for a telescopicadjustment.

Also, in Japanese Patent Application Laid-Open No. 2000-118415, in atilt-type steering apparatus for a vehicle, a distance bracket isattached to a steering column. The distance bracket is provided with apair of flanges which are extended along the sides of the steeringcolumn and which are interposed between a pair of vehicle bodyside-brackets formed with grooves for tilt adjustment. The steeringcolumn is arranged to be tiltable with respect to the body-sidebrackets, together with the distance bracket. At tilt clamping, it isarranged such that the steering column can be fixed by clamping aclamping bolt which is inserted through the grooves for tilt adjustmentof the body-side brackets to thereby press the distance bracket on thebody-side bracket with pressure.

Generally, in case of a steering column in which a distance between asteering wheel and a steering gear mechanism is short or a steeringcolumn in which a collision stroke has to be set at great, it isdifficult to securely obtain both a stroke for telescopic adjustment andthe collision stroke, in order to establish a telescopic adjustmentstructure.

To cope with a request for maintaining the steering column with a highrigidity, as disclosed in Japanese Patent Application Laid-Open No.2001-347953, such a structure is effective as that an inner column isclamped by a pair of clamp portions, which requires high precision ofthe outer periphery of the inner column and of the inner diameter of anouter jacket in order to avoid very small backlash in case with a highrigidity (particularly with high oscillation rigidity), but can beprocessed comparatively easily because of a circular section thereof.

However, in the structure disclosed in Japanese Patent ApplicationLaid-Open No. 2001-347953, it is required to separately provide astructure for preventing rotation of the inner column at a positiondifferent from that of the clamp portion.

Also, in case of a short steering column, it is difficult to secure aposition at which the structure for preventing rotation of the innercolumn is provided. It can be considered that an axial groove is formedon the inner column side in the clamp portion to cope with this problem.However, the formation of the axial groove of the inner column mayresult in that the inner column is easily flexed at clamping to therebydeteriorate the retaining rigidity.

Further, when an axial groove is plastically processed on an innercolumn in the form of a thin pipe as a deformed cross-section thereof,it is difficult to secure a dimensional accuracy, which may results inproblems such as a defective telescopic operation or backlash sensed inoperation. Further, when a plate for preventing rotation is fixed bywelding, the inner column may be deformed by welding to bring abouttelescopical defective operation.

Further, in Japanese Patent Application Laid-Open No. 2001-347953, axialslits are provided on the outer jacket at portions at which the pair ofclamp portions are formed. However, no other slit is provided on theouter jacket which is therefore formed cylindrical except the aboveportions. The other part is formed to be cylindrical. Since the outerjacket and the inner column are telescopically slidable, a gap isinevitably required therebetween. Further, since the steering shaft hasto slid telescopically, a gap is required also inside the outer jacket.As a result, backlash feeling may be caused in steering, and theretaining force of the outer jacket may be deteriorated.

Further, as disclosed in Japanese Patent Application Laid-Open No.6-219283, in the telescopic structure in which an upper side of thedistance bracket is attached to a lower side of the steering column bywelding, moments are generated on a body attaching surface, the clampportions and the center of the inner column (the center of the steeringwheel), respectively, which is disadvantageous in terms of the rigidity.

Further, a structure as disclosed in Japanese Patent ApplicationLaid-Open No. 2000-118415 in which a pair of flanges of the distancebracket extended along the sides of the steering column are interposedbetween a pair of vehicle body side brackets, is effective in terms ofthe rigidity. However, in such a structure, if it is arranged to betelescopic type, the number of the constituent parts may be increased.

SUMMARY OF THE INVENTION

In view of such circumstances as described above, an object of thepresent invention is to provide a steering apparatus for a vehicle whichis capable of maintaining a high rigidity of a steering column whilereducing the number of the constituent parts.

In order to achieve the above object, according to the presentinvention, there is provided a steering apparatus for a vehicle in whichan inner column is supported to be movable in the axial direction by anouter jacket supported by a vehicle body-side bracket, and a steeringshaft is fixed to an adjustment position by clamping the inner columnthrough the outer jacket by means of clamping means, characterized inthat:

the outer jacket is provided with slits along the entire length in theaxial direction thereof.

As described above, according to the present invention, the whole outerjacket can be flexed easily at fixing and the retaining force has nogradient in the axial direction. As a result, the retaining force can beenhanced.

Further, it is no longer required to weld the inner column to thedistance bracket since there is no other distance bracket. For thisreason, a telescopic operation becomes comparatively satisfactory sothat the steering column can be maintained with a high rigidity whilereducing the number of the constituent parts.

Also, the steering apparatus for a vehicle according to the presentinvention can be arranged such that the steering shaft is supported tobe rotatable at least two points inside the inner column, and thesteering shaft is positioned outside the inner column and is extendedand/or contracted on the lower side thereof. With this arrangement, thesteering shaft does not telescopically slide inside the inner column sothat backlash feeling sensed on the steering wheel can be reduced.

Further, the steering apparatus for a vehicle according to the presentinvention can be arranged such that the inner column is expanded to anon-circular deformed form and the inner diameter portion of the outerjacket can take a non-circular deformed form correspondingly. With thisarrangement, the main body of the inner column can be provided with thefunction of preventing rotation, and the retaining force at telescopicclamping, or the like, can be enhanced.

Further, in the steering apparatus for a vehicle according to thepresent invention, the inner column can be provided with a member for anaxial stopper for preventing rotation which is extended from the innercolumn through the slits. With this arrangement, it is possible todischarge the function of preventing rotation of the inner column andalso the function of the stopper at telescopic sliding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a tilt and/or telescopic type steeringapparatus for a vehicle according to a first embodiment of the presentinvention;

FIG. 2 is a side view of an essential portion of the tilt and/ortelescopic type steering apparatus for a vehicle shown in FIG. 1;

FIG. 3 is a plan view of the tilt and/or telescopic steering apparatustype for a vehicle shown in FIG. 1;

FIG. 4 is a view of the tilt and/or telescopic type steering apparatusfor a vehicle shown in FIG. 1, seen from diagonally below;

FIG. 5A is a transverse sectional view of the tilt and/or telescopictype steering apparatus for a vehicle shown in FIG. 1, taken along line5A-5A, and FIG. 5B is a transverse sectional view taken along line 5B-5Bof FIG. 5A;

FIG. 6 is a longitudinal sectional view of the steering apparatus in astate that an outer jacket has been removed;

FIG. 7 is a side view of a tilt and/or telescopic type steeringapparatus for a vehicle according to a second embodiment of the presentinvention;

FIG. 8 is a side view of an essential portion of the tilt and/ortelescopic type steering apparatus for a vehicle shown in FIG. 7;

FIG. 9 is a plan view of the tilt and/or telescopic type steeringapparatus for a vehicle shown in FIG. 7;

FIG. 10 is a transverse sectional view of the tilt and/or telescopictype steering apparatus for a vehicle shown in FIG. 7;

FIG. 11 is a side view of a tilt and/or telescopic type steeringapparatus for a vehicle according to a third embodiment of the presentinvention;

FIG. 12A is a side view of an essential portion of the tilt and/ortelescopic type steering apparatus for a vehicle shown in FIG. 11, FIG.12B is a transverse sectional view taken along the line 12B-12B in FIG.12A, and FIG. 12C is a transverse sectional view taken along the line12C-12C in FIG. 12A;

FIG. 13 is a plan view of the tilt and/or telescopic type steeringapparatus for a vehicle shown in FIG. 11;

FIG. 14 is a transverse sectional view of the tilt and/or telescopictype steering apparatus for a vehicle shown in FIG. 11; and

FIG. 15 is a transverse sectional view of the tilt and/or telescopictype steering apparatus for a vehicle shown in FIG. 11, for illustratingthe function thereof.

EMBODIMENT OF THE INVENTION

A steering apparatus for a vehicle according to an embodiment of thepresent invention will be described below with reference to drawings.

First Embodiment

FIG. 1 is a side view of a tilt and/or telescopic type steeringapparatus for a vehicle according to a first embodiment of the presentinvention. FIG. 2 is a side view of an essential portion of the tiltand/or telescopic type steering apparatus for a vehicle shown in FIG. 1.

FIG. 3 is a plan view of the tilt and/or telescopic type steeringapparatus for a vehicle shown in FIG. 1. FIG. 4 is a view of the tiltand/or telescopic type steering apparatus for a vehicle shown in FIG. 1,seen from diagonally below.

FIG. 5A is a transverse sectional view of the tilt and/or telescopicsteering apparatus for a vehicle shown in FIG. 1, taken along line5A-5A, and FIG. 5B is a transverse sectional view taken along line 5B-5Bof FIG. 5A.

FIG. 6 is a longitudinal sectional view of the steering apparatus in astate that an outer jacket has been removed.

In FIGS. 1 through 3 and FIG. 5B, an upper steering shaft 14 with asteering wheel (not shown) attached to a rear end thereof is supportedto be rotatable by an inner column 11 made of aluminum or copper throughbearings 12, 13. A lower end of the upper steering shaft 14 is coupledto a lower steering shaft 16 through an universal joint 15. On the frontside of the outer jacket 1 with respect to the vehicle body, there isprovided a vehicle body-side lower bracket 2 which is fixed to a vehiclebody-side strength member, and the frontal end portion of the outerjacket 1 with respect to the vehicle body is connected to this body-sidelower bracket 2 by means of a pin 3. With this arrangement, the outerjacket 1 can be tilted around the pin 3, so that the pin 3 is arrangedto play the role of a pivot at tilt adjustment. The outer jacket whichwill be described later is formed of aluminum.

The body-side lower bracket 2 is formed with a notch portion 2 a whichis engaged with the pin 3 and is open to the frontal side of thevehicle. With this arrangement, at a secondary collision, the pin 3 ismoved toward the front part of the vehicle, together with the outerjacket 1, to be removed from the vehicle body.

On the rear side of the outer jacket 1 with respect to the vehicle body,there is provided a vehicle body-side upper bracket 4 which is fixed tothe body-side strength member. Both the flanges 4 c extended in thehorizontal direction of the body-side upper bracket 4 are attached tothe body-side strength member through a bent piece 9 for removal fromthe vehicle body by means of a bolt (not shown). At a secondarycollision, the body-side upper bracket 4 can remove from the vehiclebody by means of this bent piece 9 for removal from the vehicle body.

As shown in FIG. 5A, the body-side upper bracket 4 integrally comprisesa pair of side plate portions 4 a, 4 b which are extended in anup-and-down direction. These side plate portions 4 a, 4 b are formedwith a pair of elongated holes 5 a, 5 b for the purpose of tiltadjustment. A clamping bolt 6 is inserted through these elongated holes5 a, 5 b for tilt adjustment. This clamping bolt 6 is engaged with theelongated hole 5 b at the expanded head portion 6 a thereof, so as to beprevented from rotation. A screw portion at the tip end of the clampingbolt 6 is provided with a cam and lock mechanism 8 which is operated byan operational lever 7.

The cam and lock mechanism 8 comprises, as shown in FIG. 5A, a first cammember 8 a and a second cam member 8 b. The first cam member 8 a isfitted on the clamping bolt 6 so as to rotate integrally with theoperational lever 7. The second cam member 8 b is fitted on the bolt 6to be movable, and is engaged with the elongated hole 5 a for tiltadjustment of the side plate 4 a to be movable in an up-and-downdirection along this elongated hole 5 a and to be non-rotatable by thiselongated hole 5 a. The second cam member 8 b is moved in the axialdirection while engaging with a convex part or a concave part of thefirst cam member 8 a upon rotation of the first cam member 8 a, therebyeffecting locking or releasing the locking. An adjustment nut 8 d isfixed to a screw portion of the clamping bolt 6 which is formed outsidethe cam and lock mechanism 8 through a thrust bearing 8 c.

With this arrangement, as shown in FIG. 5A, when the operational lever 7is rotated for clamping to the tilt or telescopic adjusted position, thesecond cam member 8 b of the cam and lock mechanism 8 is moved to theright in the axial direction and the pair of side plate potions 4 a, 4 bare caused to approach each other through the clamping bolt 6, therebyclamping clamp portions 10 a, 10 b which will be described later.

On the other hand, if the operational lever 7 is rotated for releasingthe clamping to the tilt or telescopic adjusted position, the second cammember 8 b of the cam and lock mechanism 8 is moved to the left in theaxial direction and the pair of side plate potions 4 a, 4 b are causedto approach each other, thereby releasing the clamped state of the clampportions 10 a, 10 b which will be described later.

In FIGS. 1 through 5B, the outer jacket 1 is extended in the axialdirection of the steering shaft, and integrally comprises side portions1 a, 1 b which are extended downward on both sides of the inner column11 in a saddle-like manner, as shown in FIG. 4. The side portions 1 a, 1b are integrally formed with the clamp portions 10 a, 10 b which supportthe inner column 11 from the outer peripheral side, at the rear endsthereof. The clamp portions 10 a, 10 b have outer surfaces which arepressed by the side plate portions 4 a, 4 b of the outer bracket 4. Atthe same time, in lower parts inside the clamp portions, a slit S isformed along the direction of the steering shaft to face each otherbelow the inner column 11.

Thus, the outer jacket 1 embraces the inner column 11 from the outerperipheral side by the use of the clamp portions 10 a, 10 b.

In the present embodiment, the inner column 11 has the minimum diameterat the rear end part 11 a thereof, a middle diameter at a middle portion11 b, and the maximum diameter at the front end portion 11 c. A firstinclined step portion 11 d and a second inclined step portion 11 e areformed between the rear end portion 11 a and the middle portion 11 b andbetween the middle portion 11 b and the front end portion 11 c,respectively. On the other hand, inside the outer jacket 1, the innerdiameter of the clamp portions 10 a, 10 b at the rear end thereofbecomes smaller than the outer diameter of the middle portion 11 b ofthe inner column 11 at the time of clamping so that the outer jacket maybe press-fitted onto the middle portion 11 b. The inner diameter of theouter jacket 1 is increased from the inclined step portion 1 d on thefront side thereof to form a gap from the inner column, and is decreasedtoward the front part to take such a form as press-fitting on the frontend portion 11 c of the inner column 11 at the time of clamping. Withthis structure, in a state that the clamp portions 10 a, 10 b areclamped by the cam and lock mechanism 8, the inner column 11 is pressedand retained by the two inner diameter portions of the outer jacket 1 atthe middle portion 11 b and the front end portion 11 c thereof.

In the present embodiment, the bearings 12 are preferably provided onthe forefront side of the middle portion 11 b of the inner column 11.

In the present embodiment, when an angle formed by the first inclinedstep portion 1 d of the outer jacket 1 and the axial direction of thesteering shaft is A and an angle formed by the second inclined stepportion 11 e of the inner column 11 and the axial direction of thesteering shaft is B, the relationship between A and B is established asA>B. In accordance with this relationship, it is possible to give theseinclined step portions with the stopper function in a telescopic slidingof the steering shaft.

The lower steering shaft 16 is, as shown in FIG. 1, formed cylindrical,and the tip end thereof is provided with a female spline portion 16 a(or a female serrated portion). A male spline portion 32 a (or a maleserrated portion) of a yoke shaft 32 which is integrally connected to ayoke 31 a of a universal joint 31 on the lower side thereof is fitted inthe female spline portion 16 a at the tip end of the lower steeringshaft 16 to be telescopically slidable. It may be arranged such that thetip end of the lower steering shaft 16 a is a male spline and the yokeshaft 32 is a female spline.

As described above, in the present embodiment, the lower steering shaft16 and the yoke shaft 32 are provided outside the inner column 11 andare arranged to be freely expandable and contractible (telescopicallyslidable) on the lower side thereof, as shown in FIG. 1. For thisreason, since the steering shaft does not telescopically slide insidethe inner column 11, backlash feeling felt on the steering wheel can bereduced.

Note that, in FIGS. 1 through 5B, a pair of coil springs 17 a, 17 b areinterposed between a pair of side plate portions 4 a, 4 b of thebody-side upper bracket and the both side portions 1 a, 1 b of the outerjacket 1. With this arrangement, it is arranged, when the clamped stateto the tilt position is released, or the like, to prevent the outerjacket 1 and the inner column 11 from falling.

In FIGS. 4 and 5A, the paired clamp portions 10 a, 10 b of the outerjacket 1 are provided with a slit S having a predetermined width alongthe entire axial direction at a lower side thereof.

A reinforcing member 18 is provided on the inner peripheral surface ofthe inner column 11 which is corresponding to this slit S. An axialstopper member 20 which is extended through the slit S for preventingrotation is fixed to this reinforcing member 18 by a screw 19.

Note that, the axial stopper member 20 for preventing rotation, thescrew 19 and a column cover attaching portion 21 are omitted in FIG. 4for easy understanding.

This axial stopper member 20 for preventing rotation is integrallyformed with the column cover attaching portion 21 and is extendeddownward.

Note that, as shown in FIGS. 1 and 2, the column cover attaching portion21 and the bent portion 20 a of the axial stopper member 20 forpreventing rotation on the rear side with respect to the vehicle bodyare respectively abut upon wall surfaces A and B (FIG. 4) at both endsin the axial direction of the clamp portions 10 a, 10 b in a telescopicsliding operation, so as to play the role of the axial stopper.

As described above, according to the present embodiment, since the clamppotions 10 a, 10 b of the outer jacket 1 are provided with the slit Salong the entire axial direction, the whole outer jacket 1 is easilyflexed at clamping. As a result, the retaining force at the clamping canbe enhanced.

Also, since the distance bracket which is conventionally used is nolonger required in the present embodiment and the welding between theinner column 11 and the distance bracket is resultantly unnecessary, atelescopic operation becomes comparatively satisfactory, so that thesteering column can be maintained at high rigidity while reducing thenumber of the constituent parts.

Inside the inner column 11, the upper steering shaft 14 is rotatablysupported at two bearings 12 and 13. In case of the present embodiment,as shown in FIG. 1, the lower steering shaft 16 and the yoke shaft 32are provided to be extendable and contractible (telescopically slidable)outside and on a lower side of the inner column 11. For this reason, thesteering shaft does not telescopically slide in the inner column 11 sothat the backlash feeling felt on the steering wheel can be reduced. Asa result, differing from the conventional Japanese Patent ApplicationLaid-Open No. 2001-347953, no backlash feeling can be sensed in steeringand the retaining force of the outer jacket can be kept high.

Further, the inner column 11 is provided with the axial stopper member20 for preventing rotation which is extend to pass through the slit Sfrom the outside of the inner column 11 to the inside of the innercolumn 11. With this axial stopper member 20 for preventing rotation,the function of preventing rotation of the inner column 11 can bedischarged and also the function of the stopper in the telescopicsliding operation can be discharged.

Further, the outer diameter of the large diameter portion 11 c of theinner column 11 described above escapes from the universal joint 15, butis caused to contact with the inner surface of the outer jacket 1, sothat the backlash of the column at the time of unclamping can be reducedand the operation can be performed smoothly. Also, at the time ofclamping, under this contact condition being kept, it is possible toeliminate the backlash and to, resultantly, enhance the oscillationrigidity of the column since the inner column 11 and the outer jacket 1are caused to abut on each other at multiple points at the time ofclamping.

Further, when the outer diameter of the rear end portion 11 a of theinner column 11 with respect to the vehicle body is set as smaller thanthe outer diameter of the middle portion 11 b which is a portion to beclamped, the inner column 11 can be inserted into the outer jacket 1from the frontal side of the vehicle to the rear side, whereby acomparatively great clearance can be provided with the outer jacket 1and the inner column 11 can be installed easily.

Second Embodiment

FIG. 7 is a side view of a tilt and/or telescopic type steeringapparatus for a vehicle according to a second embodiment of the presentinvention. FIG. 8 is a side view of an essential portion of the tiltand/or telescopic type steering apparatus for a vehicle shown in FIG. 7.

FIG. 9 is a plan view of the tilt and telescopic type steering apparatusfor a vehicle shown in FIG. 7. FIG. 10 is a transverse sectional view ofthe tilt and telescopic type steering apparatus for a vehicle shown inFIG. 7.

In case of the second embodiment, as shown in FIG. 10, the inner column11 is expanded into a non-circular deformed form and the inner diameterportions of the clamp portions 10 a, 10 b of the outer jacket 1 are alsoexpanded into non-circular deformed forms correspondingly. As a result,it is possible to provide the main body of the inner column 11 with thefunction of preventing rotation and to distribute a component forceuniformly in a vertical and horizontal directions. Thus, it is possibleto improve the retaining force at telescopic clamping, or the like.

That is, the inner column 11 is expanded into an octagonal form and theclamp portions 10 a, 10 b of the outer jacket 1 are also expanded intooctagonal forms correspondingly. With this arrangement, the clampingforce by the clamping bolt 6 acts inwardly in the axial directioneffectively, the clamping force on the inner column 11 acts verticallyon each surface of the octagonal form, and further, the reaction forceagainst the clamp potions 10 a, 10 b of the outer jacket 1 also acts oneach surface of the octagonal form. As a result, it is possible toenhance the clamping force. Other arrangements and effects are the sameas those in the foregoing embodiment, so that detailed descriptionthereof will be omitted.

Also, the clamping bolt 6 is provided at a position which is shifteddownward with respect to the central axis of the inner column 11.

Further, since the inner column 11 is formed to be octagonal, the outerdiameter portion thereof has at least one set of flat surface portionswhich are opposite to each other in parallel. For example, in FIG. 10,the flat surface portions are denoted by α and β.

Further, to be corresponding to the flat surface portions of the innercolumn 11, the inner diameter portion of the outer jacket 1 also has oneset of flat surface portions which are opposite to each other inparallel.

Third Embodiment

FIG. 11 is a side view of a tilt and telescopic type steering apparatusfor a vehicle according to a third embodiment of the present invention.FIG. 12A is a side view of an essential portion of the tilt andtelescopic type steering apparatus for a vehicle shown in FIG. 11, FIG.12B and FIG. 12C are transverse sectional views, taken along the line12B-12B and the line 12C-12C in FIG. 12A, respectively.

FIG. 13 is a plan view of the tilt and telescopic type steeringapparatus for a vehicle shown in FIG. 11.

FIG. 14 is a sectional view of the tilt and telescopic type steeringapparatus for a vehicle shown in FIG. 12A, taken along the line 14-14.FIG. 15 is a transverse sectional view of a tilt and telescopic typesteering apparatus for a vehicle shown in FIG. 11, for illustrating thefunction thereof.

In the third embodiment, an annular tension member 40 is provided on theouter periphery of the outer jacket 1 inside the body-side upper bracket4. This tension member 40 is, as shown in FIG. 14, a member in asubstantially annular form in its installed condition and is composed oftwo parts including an upper half part 41 a and a lower half part 41 b.

These upper and lower half parts 41 a and 41 b are integrated byclamping the bolt 42, thereby constituting the tension member 40. Asdescribed above, the tension member 40 is composed of two halves beforeassembling and the upper half part 41 a and the lower half part 41 b canbe integrated by clamping the bolt 42 after the assembling. As a result,the tension member 40 can be assembled easily.

As shown in FIG. 12A, in front and behind of the tension member 40 withrespect to the vehicle body, the clamp portions 10 a, 10 b of the outerjacket 1 each comprises a pair of U-shaped flanges 10 c and 10 dseparated from each other in the back and forth direction of thevehicle. The flanges 10 c and 10 d are brought into pressure contact tobe retained by the both side plates 4 a and 4 b of the body-side upperbracket 4 on both sides thereof in FIG. 14.

The annular tension member 40 described above is fitted in annulargrooves which are formed on the paired flanges 10 c and 10 d of theclamp portions 10 a and 10 b in the back and forth direction of thevehicle.

As to the forms and the structures of the inner diameter sides of theclamp portions 10 a, 10 b and the outer periphery of the inner column11, two inclined step portions are respectively provided, as in thefirst embodiment shown in FIG. 5B.

Similar to the foregoing embodiments, a slit S having a predeterminedwidth is formed on the lower sides of the paired clamp portions 10 a, 10b of the outer jacket 1 along the entire axial direction thereof.

A position of the inner column 11 corresponding to this slit S, theaxial stopper member 20 for preventing rotation which is extended topass through the slit S is fixed by a screw 19. The column coverattaching portion 21 is integrally formed with this axial stopper member20 for preventing rotation to be extended downward therefrom.

Note that, as shown in FIGS. 11, 12A, 12B and 12C, the column coverattaching portion 21 and the bent portion 20 a of the axial stoppermember 20 for preventing rotation on the rear side with respect to thevehicle are respectively caused to abut upon the wall surfaces A and B(FIGS. 12A, 12B, 12C, etc.) at both ends of the flanges 10 c, 10 d ofthe outer jacket 1 in a telescopic sliding operation, so as to play therole of the axial stopper in the axial direction.

In FIG. 14, a bolt 43 a through which a tilt adjusting groove 5 a whichis formed on the side plate 4 a of the body-side upper bracket 4 isinserted is thread-engaged with a left portion of the lower half part 41b of the tension member 40. The cam and lock mechanism 50 is provided onthis bolt 43 a between the head portion of the bolt 43 a and the sideplate 4 a through a washer and a thrust bearing 52 c. On the other hand,a bolt 43 b through which a tilt adjusting groove 5 b which is formed onthe side plate 4 b of the body-side upper bracket 4 is inserted isthread-engaged with a right portion of the lower half part 41 b of thetension member 40 to be fixed thereto. The washer is interposed betweenthe head portion of the bolt 43 a and the side plate 4 b.

The cam and lock mechanism 50 is composed of a first cam member 52 awhich is rotated integrally with an operational lever 51 and a secondcam member 52 b which is engaged with the elongated hole 5 a for tiltadjustment of the upper bracket 4 to be non-rotatable with respect tothe upper bracket 4, and is moved in the axial direction while engagingwith a convex part or a concave part of the first cam member 52 a, tofollow a rotation of the first cam member 52 a, thereby effectinglocking or unlocking.

The cam and lock mechanism 50 is loosened by operating the operationallever 51 whereby the bolts 43 a, 43 b are guided by the elongated holes5 a, 5 b for tilt adjustment, whereby the tilt and/or telescopicadjustment can be effected.

In case of the present embodiment, as shown in FIG. 15, a horizontalline (R) which passes through the centers of the bolts 43 a, 43 b isshifted downward from another horizontal line (R) which passes throughthe center (X) of the inner column 11 only by A.

As the structure is arranged as described above, when the operationallever 51 is rotated for clamping to the tilt and/or telescopicadjustment position, in FIGS. 14 and 15, in the cam and lock mechanism50, the first cam member 52 a and the bolt 43 a are moved to the left inthe axial direction, while the second cam member 52 b is moved to theright in the axial direction.

With this arrangement, the tension member 40 is pulled by the first cammember 52 a and the bolt 43 a to be moved to the left in the axialdirection. As a result, the bolt 43 b and the side plate portion 4 b onthe opposite side are moved to the left in the axial direction as ifthey were pulled by this tension member 40.

On the other hand, the side plate portion 4 a is pressed by the secondcam member 52 b to be moved to the right in the axial direction.

Accordingly, both the side plate portions 4 a, 4 b are moved to close toeach other, and resultantly press the paired flanges 10 c, 10 d in sucha manner that both flanges 10 c, 10 d come close to each other. Withthis arrangement, the paired clamp portions 10 a, 10 b are clamped.

As a result, the inner column 11 is clamped by the paired clamp portions10 a, 10 b and is clamped to the tilt and telescopic adjustmentposition.

On this occasion, since the clamp portions 10 a, 10 b of the outerjacket 1 are provided with a slit entirely along the axial directionaccording to the present embodiment, the whole outer jacket 1 can beeasily flexed at the time of clamping, and the retaining force at thetime of clamping can be enhanced.

Also, according to the present embodiment, since the annular tensionmember 40 is employed, an amount of protrusion of a lower side of thesteering column can be reduced.

Further, in the present embodiment, as shown in FIG. 15, the horizontalline (R) which passes through the centers of the bolts 43 a, 43 b isshifted downward from the horizontal line (R) which passes through thecenter (X) of the inner column 11 only by Δ.

Accordingly, as shown in FIG. 15, a pair of pressing forces (F) actdiagonally upward. As a result, a component force in the verticaldirection works on the inner column 11. When this component force is Fv,the relation that Fv=2×F·sin θ is established. However, θ is an anglewhich is formed by and between the horizontal line (R) and the pressingforce (F).

As described above, since the component force (Fv) also works, backlashof the inner column 11 can be suppressed even if the clamping force ofthe cam and lock mechanism 50 is not increased so much.

Also, assuming that the clamping force for clamping on the horizontalline (Q) is (F1) and the clamping force for clamping on the horizontalline (R) as in the present embodiment is (F2), the relation thatF2=F1·L/(L+Δ) is established. Thus, since L/(L+Δ), it is possible toobtain a great clamping force only by effecting the smaller clampingforce (F2) in accordance with the principle of leverage. As a result, itis possible to increase the retaining force (pressing force) of theinner column 11 even with a small clamping force.

Further, in the present embodiment, compared with the first and secondembodiments described above, the cam and lock clamping mechanism 50 isprovided substantially on a side of the inner column 11, and is notprotruded downward from the inner column 11. As a result, an amount ofdownward protrusion of the inner column 11 can be reduced so that theinner column 11 can be made compact, whereby a large space around theknees of the crew can be secured.

Further, in the present embodiment, since the outer diameter portion ofthe inner column 11 is formed to be non-circular and deformed and theinner diameter portions of the clamp portions 10 a, 10 b of the outerjacket 1 are also formed to be non-circular and deformed correspondinglythereto, it is possible to provide the main body of the inner column 11with the function of preventing rotation. It is also possible todistribute component forces of the clamping force in the vertical andhorizontal directions evenly so as to enhance the retaining force attelescopic clamping, or the like.

That is, the outer diameter portion of the inner column 11 is formed tobe octagonal and the inner diameter portions of the clamp portions 10 a,10 b of the outer jacket 1 is also formed to be octagonalcorrespondingly thereto. With this arrangement, the clamping force actsinward in the axial direction effectively, the clamping force on theinner column 11 acts vertically on each surface of the octagon, andfurther the reaction force against the clamp portions 10 a, 10 b of theouter jacket 1 also acts vertically on each surface of the octagon, sothat the clamping force can be enhanced.

Further, since the outer diameter portion of the inner column 11 isformed to be octagonal, this outer diameter portion has at least one setof flat surface portions which are opposed to each other in parallel.For example, the flat surface portions are denoted by α and β in FIG.15.

Further, to be corresponding to the flat surface portions of the innercolumn 11, the inner diameter portion of the outer jacket 1 has also atleast one set of flat surface portions which are opposed to each otherin parallel.

Further, since the outer diameter portion of the outer jacket 1 isformed in an octagonal, non-circular and deformed form, the tensionmember 40 is also formed to be non-circular and deformed correspondingthereto. Also to be corresponding to the flat surface portions of theouter jacket 1, the inner diameter portion of the tension member 40 hasalso at least one set of flat surface portions which are opposed to eachother in parallel.

Note that the present invention is not limited to the embodimentsdescribed above, but can be altered in various manners.

In the embodiments described above, it is arranged such that the innercolumn is provided on an upper side, while the outer jacket on a lowerside. However, it may be arranged such that the inner column is providedon the lower side and the outer jacket on the upper side. Also in theembodiments described above, the slit is formed on a lower side of theouter jacket. However, it may be formed on an upper side thereof.

It is desirable that the paired side plates 4 a, 4 b of the upperbracket 4 have the same thickness.

As described above, according to the present invention, it is possibleto enhance the retaining force at the time of clamping since the a slitis formed entirely along the axial direction of the outer jacket so thatthe whole outer jacket can be easily flexed at clamping.

Also according to the present invention, since a distance bracket whichis used conventionally is no longer required, welding between the innercolumn and the distance bracket is becomes unnecessary. As a result, atelescopic operation becomes comparatively satisfactory and the steeringcolumn can be kept at high rigidity while the number of the constituentparts can be reduced.

1. A steering apparatus for a vehicle comprising: a body-side bracketattached to a body; a column assembly supported by said body-sidebracket and including an inner column for supporting a steering shaft tobe rotatable and an outer jacket for supporting said inner column to bemovable in an axial direction; and telescopic clamping means for fixingthe steering shaft at an adjustment position by clamping said innercolumn through said outer jacket, wherein said outer jacket is providedwith a slit formed through said outer jacket over an entire axial lengthof said outer jacket.
 2. A steering apparatus for a vehicle according toclaim 1, wherein the steering shaft is supported to be rotatable atleast at two points in said inner column, and said steering shaft isextendable and contractible outside said inner column in the axialdirection and on a lower side thereof.
 3. A steering apparatus for avehicle according to claim 2, wherein said inner column has anon-circular cross-section and an inner periphery of said outer jackethas a non-circular cross-section corresponding thereto.
 4. A steeringapparatus for a vehicle according to claim 2, wherein said inner columnis provided with an axial stopper member for preventing rotation whichis extended from said inner column to pass through said slit.
 5. Asteering apparatus for a vehicle according to claim 1, wherein saidinner column has a non-circular cross-section and an inner periphery ofsaid outer jacket has a non-circular cross-section correspondingthereto.
 6. A steering apparatus for a vehicle according to claim 1,wherein said inner column is provided with an axial stopper member forpreventing rotation which is extended from said inner column to passthrough said slit.
 7. A steering apparatus for a vehicle according toclaim 1, wherein said outer jacket is pivotably connected at a lower endthereof to the vehicle body.
 8. A steering apparatus for a vehicleaccording to claim 7, further comprising a body-side lower bracket,through which the lower end of said outer jacket is pivotably connectedto the vehicle body.
 9. A steering apparatus for a vehicle comprising:an inner column for supporting a steering shaft to be rotatable; anouter jacket for supporting said inner column at an outer peripheralside thereof; a bracket attached to a vehicle body for supporting saidouter jacket such that a position of said outer jacket is adjustable;and a clamping mechanism for releasing a clamped state in which theposition of said outer jacket is fixed to said bracket so as to allowposition adjustment, wherein said outer jacket has a portion forpressing and supporting said inner column at the outer peripheral sideof said inner column, and said outer jacket is provided with a slitformed through said outer jacket over an entire axial length of saidouter jacket.
 10. A steering apparatus for a vehicle according to claim9, wherein: the outer jacket has a retaining portion, with a minimuminner diameter portion for pressing and retaining the inner column atthe outer peripheral side thereof, and an axially extending cylindricalinner diameter portion which is of larger diameter than said minimuminner diameter portion and which is connected to said retaining portionthrough an inclined step portion; and said inner column comprises acylindrical first outer diameter portion with a predetermined lengthwhich is partially pressed and supported by said minimum inner diameterportion of said outer jacket and which is extended in an axial directionto face said cylindrical inner diameter portion of said outer jacket,and a second outer diameter portion which is connected to said firstouter diameter portion through an inclined step portion, is pressed andsupported by said cylindrical inner diameter portion of said outerjacket, and has a diameter larger than that of said first outer diameterportion.
 11. A steering apparatus for a vehicle according to claim 10,wherein: said inner column supports the steering shaft at two points inthe axial direction through bearings; and a bearing on a lower side, outof said bearings, is provided at a lower end of said first outerdiameter portion of said inner column.
 12. A steering apparatus for avehicle according to claim 9, wherein said outer jacket is pivotablyconnected at a lower end thereof to a vehicle body.
 13. A steeringapparatus for a vehicle according to claim 12, further comprising abody-side lower bracket, through which the lower end of said outerjacket is pivotably connected to the vehicle body.
 14. A steeringapparatus for a vehicle comprising: a body-side bracket attached to avehicle body; a column assembly supported by said body-side bracket,said column assembly including an inner column for supporting a steeringshaft so as to be rotatable, and an outer jacket for supporting saidinner column so as to be movable in an axial direction; and a telescopicclamping mechanism operable to fix the steering shaft at an adjustmentposition by clamping said inner column through said outer jacket,wherein said outer jacket is provided with a slit formed through saidouter jacket over an entire axial length of said outer jacket.
 15. Asteering apparatus for a vehicle according to claim 14, wherein thesteering shaft is supported to be rotatable at least at two points insaid inner column, and said steering shaft is extendable andcontractible outside said inner column in the axial direction and on alower side thereof.
 16. A steering apparatus for a vehicle according toclaim 14, wherein said inner column has a non-circular cross-section andan inner periphery of said outer jacket has a non-circular cross-sectioncorresponding thereto.
 17. A steering apparatus for a vehicle accordingto claim 14, wherein said inner column is provided with an axial stoppermember for preventing rotation, which is extended from said inner columnto pass through said slit.
 18. A steering apparatus for a vehicleaccording to claim 14, wherein said outer jacket is pivotably connectedat a lower end thereof to the vehicle body.
 19. A steering apparatus fora vehicle according to claim 18, further comprising a body-side lowerbracket, through which the lower end of said outer jacket is pivotablyconnected to the vehicle body.